Effect of Si addition on the valence state of Ce in CePd3

Abstract It is observed that Si can be added to CePd 3 , which has the AuCu 3 type cubic structure, to form alloys of the type CePd 3 Si x where 0 ≤ x ≤ 0.3. Addition of Si preserves the structure but results in an expansion of the cell volume. The expansion is much larger in CePd 3 than in LaPd 3 for the same silicon concentration. In CePd 3 , cerium is in a mixed-valent state and its susceptibility tends to a temperature independent value at low temperature. However, as Si is added to CePd 3 , the susceptibility progressively increases and shows a Curie-Weiss behavior with effective moment close to that of Ce 3+ ions. Thus from lattice parameters and susceptibility measurements, it is inferred that Si addition causes a change in the valence of Ce in CePd 3 from mixed valent to nearly trivalent.